Structural Analysis of Cholesterol Binding and Sterol Selectivity by ABCG5/G8

Danny Farhat; Fatemeh Rezaei; Milica Ristovski; Yidai Yang; Albert Stancescu; Lucia Dzimkova; Sabrina Samnani; Jean-François Couture; Jyh-Yeuan Lee

doi:10.1016/j.jmb.2022.167795

Structural Analysis of Cholesterol Binding and Sterol Selectivity by ABCG5/G8

J Mol Biol. 2022 Oct 30;434(20):167795. doi: 10.1016/j.jmb.2022.167795. Epub 2022 Aug 18.

Authors

Danny Farhat¹, Fatemeh Rezaei², Milica Ristovski³, Yidai Yang², Albert Stancescu⁴, Lucia Dzimkova⁵, Sabrina Samnani⁵, Jean-François Couture², Jyh-Yeuan Lee⁶

Affiliations

¹ Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada. Electronic address: https://twitter.com/FarhDanny.
² Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
³ Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Translational and Molecular Medicine Program, Faculty of Medicine, University of Ottawa, Ontario, Ottawa, Canada.
⁴ Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Biochemistry Program, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
⁵ Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Biochemistry Program, Faculty of Science, University of Ottawa, Ottawa, Ontario, Canada.
⁶ Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada. Electronic address: Jyh-Yeuan.Lee@uOttawa.ca.

PMID: 35988751
DOI: 10.1016/j.jmb.2022.167795

Abstract

The ATP-binding cassette (ABC) sterol transporters are responsible for maintaining cholesterol homeostasis in mammals by participating in reverse cholesterol transport (RCT) or transintestinal cholesterol efflux (TICE). The heterodimeric ABCG5/G8 carries out selective sterol excretion, preventing the abnormal accumulation of plant sterols in human bodies, while homodimeric ABCG1 contributes to the biogenesis and metabolism of high-density lipoproteins. A sterol-binding site on ABCG5/G8 was proposed at the interface of the transmembrane domain and the core of lipid bilayers. In this study, we have determined the crystal structure of ABCG5/G8 in a cholesterol-bound state. The structure combined with amino acid sequence analysis shows that in the proximity of the sterol-binding site, a highly conserved phenylalanine array supports functional implications for ABCG cholesterol/sterol transporters. Lastly, in silico docking analysis of cholesterol and stigmasterol (a plant sterol) suggests sterol-binding selectivity on ABCG5/G8, but not ABCG1. Together, our results provide a structural basis for cholesterol binding on ABCG5/G8 and the sterol selectivity by ABCG transporters.

Keywords: ABCG5; ABCG8; X-ray crystallography; molecular docking; sterol selectivity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

ATP Binding Cassette Transporter, Subfamily G, Member 5* / chemistry
ATP Binding Cassette Transporter, Subfamily G, Member 5* / genetics
ATP Binding Cassette Transporter, Subfamily G, Member 8* / chemistry
ATP Binding Cassette Transporter, Subfamily G, Member 8* / genetics
Cholesterol* / chemistry
Cholesterol* / metabolism
Cryoelectron Microscopy
Humans
Lipid Bilayers / chemistry
Lipoproteins, HDL / metabolism
Phenylalanine / metabolism
Phytosterols / metabolism
Protein Binding
Protein Conformation
Stigmasterol / metabolism

Substances

ABCG5 protein, human
ABCG8 protein, human
ATP Binding Cassette Transporter, Subfamily G, Member 5
ATP Binding Cassette Transporter, Subfamily G, Member 8
Lipid Bilayers
Lipoproteins, HDL
Phytosterols
Phenylalanine
Cholesterol
Stigmasterol

Grants and funding

PJT-180640/CIHR/Canada